Effects of Seasonal Redox Processes Involving iron on the Chemistry of Periodically Reduced Soils

Abstract

The entirely different chemical properties of Fe(III) and Fe(II), combined with the ubiquity of Fe in soils, have important consequences for the chemistry of soil and soil solution in alternating oxidized and reduced conditions. This Chapter gives a general outline of reduction processes in soils, and gives an account of the effect of reduction processes involving Fe on (1) solid phase Fe forms, (2) pH, (3) redox potential, (4) the composition of the soil solution, and (5) the composition of the soil cation exchange complex. The processes discussed here proceed relatively quickly, i.e., within weeks to months. Long-term effects of these processes on the chemistry, mineralogy, and morphology of soils will be dealt with in the next Chapter (van Breemen, 1987a). For review articles on soil redox processes in general, reference is made to Ponnamperuma (1972), Patrick and Reddy (1978), and Yamane (1978).